Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK; Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK. Electronic address:
Published: March 2023
AI Article Synopsis
Article Abstract
Mitochondrial activity differs markedly between organs, but it is not known how and when this arises. Here we show that cell lineage-specific expression profiles involving essential mitochondrial genes emerge at an early stage in mouse development, including tissue-specific isoforms present before organ formation. However, the nuclear transcriptional signatures were not independent of organelle function. Genetically disrupting intra-mitochondrial protein synthesis with two different mtDNA mutations induced cell lineage-specific compensatory responses, including molecular pathways not previously implicated in organellar maintenance. We saw downregulation of genes whose expression is known to exacerbate the effects of exogenous mitochondrial toxins, indicating a transcriptional adaptation to mitochondrial dysfunction during embryonic development. The compensatory pathways were both tissue and mutation specific and under the control of transcription factors which promote organelle resilience. These are likely to contribute to the tissue specificity which characterizes human mitochondrial diseases and are potential targets for organ-directed treatments.
Pancreatic ductal adenocarcinoma (PDA) is a lethal malignancy characterized by insidious onset and lack of effective therapy. The molecular pathogenesis of PDA remains to be understood fully. Transcriptional factor GATA6 is an important transcriptional regulator in normal pancreas development, particularly in the initial specification and differentiation of the pancreas.
The canonical model of tumor suppressor gene (TSG)-mediated oncogenesis posits that loss of both alleles is necessary for inactivation. Here, through allele-specific analysis of sequencing data from 48,179 cancer patients, we define the prevalence, selective pressure for, and functional consequences of biallelic inactivation across TSGs. TSGs largely assort into distinct classes associated with either pan-cancer (Class 1) or lineage-specific (Class 2) patterns of selection for biallelic loss, although some TSGs are predominantly monoallelically inactivated (Class 3/4).
Cellular identity requires the concerted action of multiple transcription factors (TFs) bound together to enhancers of cell-type-specific genes. Despite TFs recognizing specific DNA motifs within accessible chromatin, this information is insufficient to explain how TFs select enhancers. Here we compared four different TF combinations that induce different cell states, analysing TF genome occupancy, chromatin accessibility, nucleosome positioning and 3D genome organization at the nucleosome resolution.
The phylum Apicomplexa comprises eukaryotic parasites that cause fatal diseases affecting millions of people and animals worldwide. Their mitochondrial genomes have been significantly reduced, leaving only three protein-coding genes and highly fragmented mitoribosomal rRNAs, raising challenging questions about mitoribosome composition, assembly and structure. Our study reveals how Toxoplasma gondii assembles over 40 mt-rRNA fragments using exclusively nuclear-encoded mitoribosomal proteins and three lineage-specific families of RNA-binding proteins.
Clinical and experimental evidence indicates that alcohol use causes various abnormalities in the immune system and compromises immune functions. However, the mechanistic understanding of ethanol's effects on the immune system remains limited. Cyclic AMP (cAMP) regulates multiple processes, including immune responses.
